import * as THREE from "three";

export class MeshLine extends THREE.BufferGeometry {
	constructor() {
		super();
		this.isMeshLine = true;
		this.type = 'MeshLine';

		this.positions = [];

		this.previous = [];
		this.next = [];
		this.side = [];
		this.width = [];
		this.indices_array = [];
		this.uvs = [];
		this.counters = [];
		this._points = [];
		this._geom = null;

		this.widthCallback = null;

		// Used to raycast
		this.matrixWorld = new THREE.Matrix4();

		Object.defineProperties(this, {
			// this is now a bufferGeometry
			// add getter to support previous api
			geometry: {
				enumerable: true,
				get: function() {
					return this;
				},
			},
			geom: {
				enumerable: true,
				get: function() {
					return this._geom;
				},
				set: function(value) {
					this.setGeometry(value, this.widthCallback);
				},
			},
			// for declaritive architectures
			// to return the same value that sets the points
			// eg. this.points = points
			// console.log(this.points) -> points
			points: {
				enumerable: true,
				get: function() {
					return this._points;
				},
				set: function(value) {
					this.setPoints(value, this.widthCallback);
				},
			},
		});
	}
}

MeshLine.prototype.setMatrixWorld = function(matrixWorld) {
	this.matrixWorld = matrixWorld;
};

// setting via a geometry is rather superfluous
// as you're creating a unecessary geometry just to throw away
// but exists to support previous api
MeshLine.prototype.setGeometry = function(g, c) {
	// as the input geometry are mutated we store them
	// for later retreival when necessary (declaritive architectures)
	this._geometry = g;
	this.setPoints(g.getAttribute("position").array, c);
};

MeshLine.prototype.setPoints = function(points, wcb) {
	if (!(points instanceof Float32Array) && !(points instanceof Array)) {
		console.error(
			"ERROR: The BufferArray of points is not instancied correctly."
		);
		return;
	}
	// as the points are mutated we store them
	// for later retreival when necessary (declaritive architectures)
	this._points = points;
	this.widthCallback = wcb;
	this.positions = [];
	this.counters = [];
	if (points.length && points[0] instanceof THREE.Vector3) {
		// could transform Vector3 array into the array used below
		// but this approach will only loop through the array once
		// and is more performant
		for (var j = 0; j < points.length; j++) {
			var p = points[j];
			var c = j / points.length;
			this.positions.push(p.x, p.y, p.z);
			this.positions.push(p.x, p.y, p.z);
			this.counters.push(c);
			this.counters.push(c);
		}
	} else {
		for (var j = 0; j < points.length; j += 3) {
			var c = j / points.length;
			this.positions.push(points[j], points[j + 1], points[j + 2]);
			this.positions.push(points[j], points[j + 1], points[j + 2]);
			this.counters.push(c);
			this.counters.push(c);
		}
	}
	this.process();
};

function MeshLineRaycast(raycaster, intersects) {
	var inverseMatrix = new THREE.Matrix4();
	var ray = new THREE.Ray();
	var sphere = new THREE.Sphere();
	var interRay = new THREE.Vector3();
	var geometry = this.geometry;
	// Checking boundingSphere distance to ray

	if (!geometry.boundingSphere) geometry.computeBoundingSphere();
	sphere.copy(geometry.boundingSphere);
	sphere.applyMatrix4(this.matrixWorld);

	if (raycaster.ray.intersectSphere(sphere, interRay) === false) {
		return;
	}

	inverseMatrix.copy(this.matrixWorld).invert();
	ray.copy(raycaster.ray).applyMatrix4(inverseMatrix);

	var vStart = new THREE.Vector3();
	var vEnd = new THREE.Vector3();
	var interSegment = new THREE.Vector3();
	var step = this instanceof THREE.LineSegments ? 2 : 1;
	var index = geometry.index;
	var attributes = geometry.attributes;

	if (index !== null) {
		var indices = index.array;
		var positions = attributes.position.array;
		var widths = attributes.width.array;

		for (var i = 0, l = indices.length - 1; i < l; i += step) {
			var a = indices[i];
			var b = indices[i + 1];

			vStart.fromArray(positions, a * 3);
			vEnd.fromArray(positions, b * 3);
			var width = widths[Math.floor(i / 3)] !== undefined ? widths[Math.floor(i / 3)] : 1;
			var precision = raycaster.params.Line.threshold + (this.material.lineWidth * width) / 2;
			var precisionSq = precision * precision;

			var distSq = ray.distanceSqToSegment(vStart, vEnd, interRay, interSegment);

			if (distSq > precisionSq) continue;

			interRay.applyMatrix4(this.matrixWorld); // Move back to world space for distance calculation

			var distance = raycaster.ray.origin.distanceTo(interRay);

			if (distance < raycaster.near || distance > raycaster.far) continue;

			intersects.push({
				distance: distance,
				// What do we want? intersection point on the ray or on the segment??
				// point: raycaster.ray.at( distance ),
				point: interSegment.clone().applyMatrix4(this.matrixWorld),
				index: i,
				face: null,
				faceIndex: null,
				object: this,
			});
			// make event only fire once
			i = l;
		}
	}
}
MeshLine.prototype.raycast = MeshLineRaycast;
MeshLine.prototype.compareV3 = function(a, b) {
	var aa = a * 6;
	var ab = b * 6;
	return (
		this.positions[aa] === this.positions[ab] &&
		this.positions[aa + 1] === this.positions[ab + 1] &&
		this.positions[aa + 2] === this.positions[ab + 2]
	);
};

MeshLine.prototype.copyV3 = function(a) {
	var aa = a * 6;
	return [this.positions[aa], this.positions[aa + 1], this.positions[aa + 2]];
};

MeshLine.prototype.process = function() {
	var l = this.positions.length / 6;

	this.previous = [];
	this.next = [];
	this.side = [];
	this.width = [];
	this.indices_array = [];
	this.uvs = [];

	var w;

	var v;
	// initial previous points
	if (this.compareV3(0, l - 1)) {
		v = this.copyV3(l - 2);
	} else {
		v = this.copyV3(0);
	}
	this.previous.push(v[0], v[1], v[2]);
	this.previous.push(v[0], v[1], v[2]);

	for (var j = 0; j < l; j++) {
		// sides
		this.side.push(1);
		this.side.push(-1);

		// widths
		if (this.widthCallback) w = this.widthCallback(j / (l - 1));
		else w = 1;
		this.width.push(w);
		this.width.push(w);

		// uvs
		this.uvs.push(j / (l - 1), 0);
		this.uvs.push(j / (l - 1), 1);

		if (j < l - 1) {
			// points previous to poisitions
			v = this.copyV3(j);
			this.previous.push(v[0], v[1], v[2]);
			this.previous.push(v[0], v[1], v[2]);

			// indices
			var n = j * 2;
			this.indices_array.push(n, n + 1, n + 2);
			this.indices_array.push(n + 2, n + 1, n + 3);
		}
		if (j > 0) {
			// points after poisitions
			v = this.copyV3(j);
			this.next.push(v[0], v[1], v[2]);
			this.next.push(v[0], v[1], v[2]);
		}
	}

	// last next point
	if (this.compareV3(l - 1, 0)) {
		v = this.copyV3(1);
	} else {
		v = this.copyV3(l - 1);
	}
	this.next.push(v[0], v[1], v[2]);
	this.next.push(v[0], v[1], v[2]);

	// redefining the attribute seems to prevent range errors
	// if the user sets a differing number of vertices
	if (!this._attributes || this._attributes.position.count !== this.positions.length) {
		this._attributes = {
			position: new THREE.BufferAttribute(new Float32Array(this.positions), 3),
			previous: new THREE.BufferAttribute(new Float32Array(this.previous), 3),
			next: new THREE.BufferAttribute(new Float32Array(this.next), 3),
			side: new THREE.BufferAttribute(new Float32Array(this.side), 1),
			width: new THREE.BufferAttribute(new Float32Array(this.width), 1),
			uv: new THREE.BufferAttribute(new Float32Array(this.uvs), 2),
			index: new THREE.BufferAttribute(new Uint16Array(this.indices_array), 1),
			counters: new THREE.BufferAttribute(new Float32Array(this.counters), 1),
		};
	} else {
		this._attributes.position.copyArray(new Float32Array(this.positions));
		this._attributes.position.needsUpdate = true;
		this._attributes.previous.copyArray(new Float32Array(this.previous));
		this._attributes.previous.needsUpdate = true;
		this._attributes.next.copyArray(new Float32Array(this.next));
		this._attributes.next.needsUpdate = true;
		this._attributes.side.copyArray(new Float32Array(this.side));
		this._attributes.side.needsUpdate = true;
		this._attributes.width.copyArray(new Float32Array(this.width));
		this._attributes.width.needsUpdate = true;
		this._attributes.uv.copyArray(new Float32Array(this.uvs));
		this._attributes.uv.needsUpdate = true;
		this._attributes.index.copyArray(new Uint16Array(this.indices_array));
		this._attributes.index.needsUpdate = true;
	}

	this.setAttribute('position', this._attributes.position);
	this.setAttribute('previous', this._attributes.previous);
	this.setAttribute('next', this._attributes.next);
	this.setAttribute('side', this._attributes.side);
	this.setAttribute('width', this._attributes.width);
	this.setAttribute('uv', this._attributes.uv);
	this.setAttribute('counters', this._attributes.counters);

	this.setIndex(this._attributes.index);

	this.computeBoundingSphere();
	this.computeBoundingBox();
};

function memcpy(src, srcOffset, dst, dstOffset, length) {
	var i;

	src = src.subarray || src.slice ? src : src.buffer;
	dst = dst.subarray || dst.slice ? dst : dst.buffer;

	src = srcOffset
		? src.subarray
			? src.subarray(srcOffset, length && srcOffset + length)
			: src.slice(srcOffset, length && srcOffset + length)
		: src;

	if (dst.set) {
		dst.set(src, dstOffset);
	} else {
		for (i = 0; i < src.length; i++) {
			dst[i + dstOffset] = src[i];
		}
	}

	return dst;
}

/**
 * Fast method to advance the line by one position.  The oldest position is removed.
 * @param position
 */
MeshLine.prototype.advance = function(position) {
	var positions = this._attributes.position.array;
	var previous = this._attributes.previous.array;
	var next = this._attributes.next.array;
	var l = positions.length;

	// PREVIOUS
	memcpy(positions, 0, previous, 0, l);

	// POSITIONS
	memcpy(positions, 6, positions, 0, l - 6);

	positions[l - 6] = position.x;
	positions[l - 5] = position.y;
	positions[l - 4] = position.z;
	positions[l - 3] = position.x;
	positions[l - 2] = position.y;
	positions[l - 1] = position.z;

	// NEXT
	memcpy(positions, 6, next, 0, l - 6);

	next[l - 6] = position.x;
	next[l - 5] = position.y;
	next[l - 4] = position.z;
	next[l - 3] = position.x;
	next[l - 2] = position.y;
	next[l - 1] = position.z;

	this._attributes.position.needsUpdate = true;
	this._attributes.previous.needsUpdate = true;
	this._attributes.next.needsUpdate = true;
};

THREE.ShaderChunk['meshline_vert'] = [
	'',
	THREE.ShaderChunk.logdepthbuf_pars_vertex,
	THREE.ShaderChunk.fog_pars_vertex,
	'',
	'attribute vec3 previous;',
	'attribute vec3 next;',
	'attribute float side;',
	'attribute float width;',
	'attribute float counters;',
	'',
	'uniform vec2 resolution;',
	'uniform float lineWidth;',
	'uniform vec3 color;',
	'uniform float opacity;',
	'uniform float sizeAttenuation;',
	'',
	'varying vec2 vUV;',
	'varying vec4 vColor;',
	'varying float vCounters;',
	'',
	'vec2 fix( vec4 i, float aspect ) {',
	'',
	'    vec2 res = i.xy / i.w;',
	'    res.x *= aspect;',
	'	 vCounters = counters;',
	'    return res;',
	'',
	'}',
	'',
	'void main() {',
	'',
	'    float aspect = resolution.x / resolution.y;',
	'',
	'    vColor = vec4( color, opacity );',
	'    vUV = uv;',
	'',
	'    mat4 m = projectionMatrix * modelViewMatrix;',
	'    vec4 finalPosition = m * vec4( position, 1.0 );',
	'    vec4 prevPos = m * vec4( previous, 1.0 );',
	'    vec4 nextPos = m * vec4( next, 1.0 );',
	'',
	'    vec2 currentP = fix( finalPosition, aspect );',
	'    vec2 prevP = fix( prevPos, aspect );',
	'    vec2 nextP = fix( nextPos, aspect );',
	'',
	'    float w = lineWidth * width;',
	'',
	'    vec2 dir;',
	'    if( nextP == currentP ) dir = normalize( currentP - prevP );',
	'    else if( prevP == currentP ) dir = normalize( nextP - currentP );',
	'    else {',
	'        vec2 dir1 = normalize( currentP - prevP );',
	'        vec2 dir2 = normalize( nextP - currentP );',
	'        dir = normalize( dir1 + dir2 );',
	'',
	'        vec2 perp = vec2( -dir1.y, dir1.x );',
	'        vec2 miter = vec2( -dir.y, dir.x );',
	'        //w = clamp( w / dot( miter, perp ), 0., 4. * lineWidth * width );',
	'',
	'    }',
	'',
	'    //vec2 normal = ( cross( vec3( dir, 0. ), vec3( 0., 0., 1. ) ) ).xy;',
	'    vec4 normal = vec4( -dir.y, dir.x, 0., 1. );',
	'    normal.xy *= .5 * w;',
	'    normal *= projectionMatrix;',
	'    if( sizeAttenuation == 0. ) {',
	'        normal.xy *= finalPosition.w;',
	'        normal.xy /= ( vec4( resolution, 0., 1. ) * projectionMatrix ).xy;',
	'    }',
	'',
	'    finalPosition.xy += normal.xy * side;',
	'',
	'    gl_Position = finalPosition;',
	'',
	THREE.ShaderChunk.logdepthbuf_vertex,
	THREE.ShaderChunk.fog_vertex && '    vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
	THREE.ShaderChunk.fog_vertex,
	'}',
].join('\n');

THREE.ShaderChunk['meshline_frag'] = [
	'',
	THREE.ShaderChunk.fog_pars_fragment,
	THREE.ShaderChunk.logdepthbuf_pars_fragment,
	'',
	'uniform sampler2D map;',
	'uniform sampler2D alphaMap;',
	'uniform float useMap;',
	'uniform float useAlphaMap;',
	'uniform float useDash;',
	'uniform float dashArray;',
	'uniform float dashOffset;',
	'uniform float dashRatio;',
	'uniform float visibility;',
	'uniform float alphaTest;',
	'uniform vec2 repeat;',
	'uniform vec2 uOffset;',
	'',
	'varying vec2 vUV;',
	'varying vec4 vColor;',
	'varying float vCounters;',
	'',
	'void main() {',
	'',
	THREE.ShaderChunk.logdepthbuf_fragment,
	'',
	'    vec4 c = vColor;',
	'    if( useMap == 1. ) c *= texture2D( map, vUV * repeat + uOffset );',
	'    if( useAlphaMap == 1. ) c.a *= texture2D( alphaMap, vUV * repeat ).a;',
	'    if( c.a < alphaTest ) discard;',
	'    if( useDash == 1. ){',
	'        c.a *= ceil(mod(vCounters + dashOffset, dashArray) - (dashArray * dashRatio));',
	'    }',
	'    gl_FragColor = c;',
	'    gl_FragColor.a *= step(vCounters, visibility);',
	'',
	THREE.ShaderChunk.fog_fragment,
	'}',
].join('\n');

export class MeshLineMaterial extends THREE.ShaderMaterial {
	constructor(parameters) {
		super({
			uniforms: Object.assign({}, THREE.UniformsLib.fog, {
				lineWidth: {value: 1},
				map: {value: null},
				useMap: {value: 0},
				alphaMap: {value: null},
				useAlphaMap: {value: 0},
				color: {value: new THREE.Color(0xffffff)},
				opacity: {value: 1},
				resolution: {value: new THREE.Vector2(1, 1)},
				sizeAttenuation: {value: 1},
				dashArray: {value: 0},
				dashOffset: {value: 0},
				dashRatio: {value: 0.5},
				useDash: {value: 0},
				visibility: {value: 1},
				alphaTest: {value: 0},
				repeat: {value: new THREE.Vector2(1, 1)},
				uOffset: {value: new THREE.Vector2(0, 0)},
			}),

			vertexShader: THREE.ShaderChunk.meshline_vert,

			fragmentShader: THREE.ShaderChunk.meshline_frag,
		});
		this.isMeshLineMaterial = true;
		this.type = 'MeshLineMaterial';

		Object.defineProperties(this, {
			lineWidth: {
				enumerable: true,
				get: function() {
					return this.uniforms.lineWidth.value;
				},
				set: function(value) {
					this.uniforms.lineWidth.value = value;
				},
			},
			map: {
				enumerable: true,
				get: function() {
					return this.uniforms.map.value;
				},
				set: function(value) {
					this.uniforms.map.value = value;
				},
			},
			useMap: {
				enumerable: true,
				get: function() {
					return this.uniforms.useMap.value;
				},
				set: function(value) {
					this.uniforms.useMap.value = value;
				},
			},
			alphaMap: {
				enumerable: true,
				get: function() {
					return this.uniforms.alphaMap.value;
				},
				set: function(value) {
					this.uniforms.alphaMap.value = value;
				},
			},
			useAlphaMap: {
				enumerable: true,
				get: function() {
					return this.uniforms.useAlphaMap.value;
				},
				set: function(value) {
					this.uniforms.useAlphaMap.value = value;
				},
			},
			color: {
				enumerable: true,
				get: function() {
					return this.uniforms.color.value;
				},
				set: function(value) {
					this.uniforms.color.value = value;
				},
			},
			opacity: {
				enumerable: true,
				get: function() {
					return this.uniforms.opacity.value;
				},
				set: function(value) {
					this.uniforms.opacity.value = value;
				},
			},
			resolution: {
				enumerable: true,
				get: function() {
					return this.uniforms.resolution.value;
				},
				set: function(value) {
					this.uniforms.resolution.value.copy(value);
				},
			},
			sizeAttenuation: {
				enumerable: true,
				get: function() {
					return this.uniforms.sizeAttenuation.value;
				},
				set: function(value) {
					this.uniforms.sizeAttenuation.value = value;
				},
			},
			dashArray: {
				enumerable: true,
				get: function() {
					return this.uniforms.dashArray.value;
				},
				set: function(value) {
					this.uniforms.dashArray.value = value;
					this.useDash = value !== 0 ? 1 : 0;
				},
			},
			dashOffset: {
				enumerable: true,
				get: function() {
					return this.uniforms.dashOffset.value;
				},
				set: function(value) {
					this.uniforms.dashOffset.value = value;
				},
			},
			dashRatio: {
				enumerable: true,
				get: function() {
					return this.uniforms.dashRatio.value;
				},
				set: function(value) {
					this.uniforms.dashRatio.value = value;
				},
			},
			useDash: {
				enumerable: true,
				get: function() {
					return this.uniforms.useDash.value;
				},
				set: function(value) {
					this.uniforms.useDash.value = value;
				},
			},
			visibility: {
				enumerable: true,
				get: function() {
					return this.uniforms.visibility.value;
				},
				set: function(value) {
					this.uniforms.visibility.value = value;
				},
			},
			alphaTest: {
				enumerable: true,
				get: function() {
					return this.uniforms.alphaTest.value;
				},
				set: function(value) {
					this.uniforms.alphaTest.value = value;
				},
			},
			repeat: {
				enumerable: true,
				get: function() {
					return this.uniforms.repeat.value;
				},
				set: function(value) {
					this.uniforms.repeat.value.copy(value);
				},
			},
		});

		this.setValues(parameters);
	}
}

MeshLineMaterial.prototype.copy = function(source) {
	THREE.ShaderMaterial.prototype.copy.call(this, source);

	this.lineWidth = source.lineWidth;
	this.map = source.map;
	this.useMap = source.useMap;
	this.alphaMap = source.alphaMap;
	this.useAlphaMap = source.useAlphaMap;
	this.color.copy(source.color);
	this.opacity = source.opacity;
	this.resolution.copy(source.resolution);
	this.sizeAttenuation = source.sizeAttenuation;
	this.dashArray.copy(source.dashArray);
	this.dashOffset.copy(source.dashOffset);
	this.dashRatio.copy(source.dashRatio);
	this.useDash = source.useDash;
	this.visibility = source.visibility;
	this.alphaTest = source.alphaTest;
	this.repeat.copy(source.repeat);

	return this;
};
